Semiconductor Light Emitting Device Eutectic Bonding Layers
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Solution Overview
Problem
Conventional semiconductor light-emitting devices face issues with insufficient bonding strength between the support substrate and the semiconductor element multilayer, leading to potential separation and cracking, which can result in increased operating voltage and reduced reliability.
Innovation Solution
The use of a eutectic alloy with a low melting point for bonding, accompanied by first and third eutectic alloy layers with higher melting points, allows for bonding at a low temperature while relaxing thermal stress, and the second eutectic alloy layer with a larger thermal expansion coefficient is strategically positioned to enhance bonding strength and heat radiation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional bonding methods are used to bond the semiconductor element multilayer to the support substrate, then bonding can be achieved, but bonding strength is insufficient leading to separation and cracking
Solution Approach 1:
The patent changes the bonding temperature parameter from conventional high temperature to low temperature (using eutectic alloy melting point), which prevents thermal stress and cracking while achieving sufficient bonding strength. This parameter change resolves the contradiction between bonding strength and device reliability.
Solution Approach 2:
The patent uses a composite bonding layer structure consisting of multiple layers with different materials (eutectic alloy, first bonding layer, second bonding layer, third bonding layer) having different thermal expansion coefficients. This composite structure enhances bonding strength while accommodating thermal stress, preventing separation and cracking.
2Strength
If high bonding temperature is used to improve bonding strength, then bonding can be achieved, but thermal stress causes cracking and separation
Solution Approach 1:
The patent changes the bonding temperature parameter from high temperature to low temperature by utilizing the eutectic alloy's low melting point. This eliminates thermal stress and cracking while achieving adequate bonding strength through the eutectic bonding mechanism.
Solution Approach 2:
The patent utilizes the phase transition of the eutectic alloy from solid to liquid at its low melting point during bonding, then solidifies to form a strong bond. This phase transition enables bonding at low temperature, avoiding thermal stress and cracking.
3Ease of manufacture
If the bonding layer structure is simplified to reduce complexity, then manufacturing is easier, but bonding strength and heat radiation efficiency are reduced
Solution Approach 1:
The patent employs a composite bonding layer structure with multiple layers having different thermal expansion coefficients. This composite structure simultaneously achieves strong bonding, effective heat radiation, and stress management, resolving the contradiction between manufacturing complexity and performance.
Solution Approach 2:
The patent assigns different materials and properties to different layers of the bonding structure. Each layer has specific local quality (thermal expansion coefficient, melting point) optimized for its function, achieving overall superior bonding strength and heat radiation efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves bonding strength, reduces the risk of separation, maintains low operating voltage, and ensures efficient heat radiation, resulting in a semiconductor light-emitting device with high reliability.
Implementation Method 1
a first eutectic alloy layer and a third eutectic alloy layer having relatively high melting points are provided on the side of the support substrate and on the side of the semiconductor element layers, and a second eutectic alloy layer having a relatively low melting point is provided between the first eutectic alloy layer and the third eutectic alloy layer
Implementation Method 2
the thermal expansion coefficient of the second eutectic alloy layer is preferably larger than the thermal expansion coefficients of the first eutectic alloy layer and the third eutectic alloy layer
Data Source
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AI summary
A semiconductor light-emitting device having high reliability is obtained while suppressing separation between a support substrate and a semiconductor element layer. This semiconductor light-emitting device includes a support substrate (1), a first bonding layer (2a) formed on the support substrate (1), a second bonding layer (2b) formed on the first bonding layer (2a), a third bonding layer (2c) formed on the second bonding layer (2b), and a semiconductor element layer (3) formed on the third bonding layer (2c). The melting point of the second bonding layer (2b) is lower than the melting points of the first bonding layer (2a) and the third bonding layer (2c).